Watershed Issues

By Dale Norrington, Master Gardener


Collectively, gardeners can significantly impact nonpoint source water pollution, a current "hot topic" watershed issue on the central coast.


Legislation specifies beneficial uses for water contained in California's rivers, lakes, ground water basins, and along its shoreline.  Beneficial uses include domestic, industrial, agricultural, and municipal supply, power generation, recreation, esthetic enjoyment, navigation, and preservation of fish and wildlife.  Legislation also specifies water quality criteria necessary to protect these uses.

Two general categories of pollution must be controlled to meet these criteria: point source, and nonpoint source. 

Point sources of pollution are relatively simple to identify and have been addressed for decades.  They include discharges from well-defined sources such as pipes and ditches.

Nonpoint sources are generally widespread, dispersed, more difficult to identify, and have generally only more recently been addressed.  They often include water which washes off impervious surfaces such as rooftops, patios, sidewalks, driveways, streets, and parking lots, as well as water which washes across gardens, agricultural lands, and other areas with exposed soil including construction, mining, and logging sites.  They may include rural roads, and roads into remote areas used for fire protection, logging, mining, and recreation.

Sediment, nutrients, bacteria and viruses, and toxics including heavy metals, pesticides, and organic chemicals may be present in water from nonpoint sources, and ultimately, negatively impact ground water, streams, lakes, and inshore waters.

At issue may be individual willingness to learn, and sometimes to change.  An important change may be to take time to read and follow label directions on pesticides and fertilizers, or to study, gain understanding, and practice integrated pest management procedures.  Mulching, erosion control, use of native plants and porous paving materials, on site retention of runoff, appropriate disposal of excess pesticides, fertilizers, paint, oil, lacquer, gas, and their containers are all ways gardeners can have positive impact. 

University of California Cooperative Extension Master Gardener Volunteers can provide additional gardening information upon request .Call the San Luis Obispo office at 781-5939 on Mondays and Thursdays from 1 to 5 PM.  You may also call the Paso Robles office at 237-3100 on Wednesdays from 9 AM to 12 PM.  The San Luis Obispo Master Gardeners website is at http://groups.ucanr.org/slomg/.  Questions can be e-mailed to: mgsanluisobispo@ucdavis.edu.